another thing is never trust the size of the tire on the side wall...i kept wondering about why my speedo was so off with my superchips set on 31 and it finally dawned on me the other day when I messured the tires on it that they are said to be 31x10.50's they are only about 29.7-29.8 inches tall and i have found 29.75 on the superchips is the closest to being correct with the road side things. so when I get my new tires that are said to be 31.8" i'll set it at 31.75"

 

Hmm. never thought of that. But makes total sense, that's why they always say to use loaded radius. hmm.